A Planned Parenthood clinic in Colorado Springs. The Justice Department appears to be laying the groundwork for an investigation into the transfer of fetal tissue by abortion providers including Planned Parenthood.CreditCreditJerilee Bennett/The Gazette, via Associated Press

WASHINGTON — The Justice Department appears to be laying the groundwork for an investigation into the transfer of fetal tissue by abortion providers, including Planned Parenthood, picking up where several Republican-led inquiries in Congress had dropped off last year.

In a letter to the Senate Judiciary Committee on Thursday, Stephen E. Boyd, the assistant attorney general for legislative affairs, requested unredacted documents underlying a 2016 investigation by the committee into the exchange of human fetal tissue that had been donated for research by women who get abortions.

“At this point, the records are intended for investigative use only,” Mr. Boyd wrote, adding that it might take a vote by the Senate to allow the documents to be used in formal legal proceedings.

His letter, a copy of which was obtained by The New York Times, did not name Planned Parenthood or other groups implicated in the Judiciary Committee report. Nor did it give much indication of how expansive or developed the department’s work was. A Justice Department spokeswoman, Sarah Isgur Flores, declined to comment on Friday, citing department policy against commenting on or confirming the existence of an ongoing investigation.

But the decision by Attorney General Jeff Sessions’s Justice Department is sure to breathe new life into a bruising fight over abortion and particularly the handling of fetal body parts after an abortion is complete. And it appeared to offer social conservatives a long-sought victory, moving the Planned Parenthood probes out off Capitol Hill to the Department of Justice.

The issue has long inflamed the right, but most recently flared up in response to the release in 2015 of a heavily edited video purporting to show a Planned Parenthood official discussing the illegal sale of fetal parts. That video prompted House Republicans to form a select investigative panel that spent 15 months examining fetal tissues sale. The panel produced a 471-page report last December but no charges.

On Friday, anti-abortion groups welcomed the news that the Justice Department may have picked up the cause, and they urged Congress to cut off federal funding to Planned Parenthood, a favorite target, in light of the investigation.

“March for Life welcomes any action taken by the D.O.J. that signals a serious, thorough investigation into Planned Parenthood’s profitable practice of selling baby body parts,” the group’s president, Jeanne Mancini, said. “Taxpayer funds should not support an organization under federal investigation for such serious matters.”

Dana Singiser, Planned Parenthood’s vice president for government relations, said the group had done nothing wrong and pointed to investigations into its handling of fetal tissue by other congressional committees and more than a dozen states, which concluded the same thing.

“These accusations are baseless, and a part of a widely discredited attempt to end access to reproductive health care at Planned Parenthood,” she said in a statement. “Planned Parenthood has never, and would never, profit while facilitating its patients’ choice to donate fetal tissue for use in important medical research.”

Democrats on Capitol Hill castigated the department for the “flagrant politicization of its mission,” as Representative Jerrold Nadler of New York, the top Democrat on the House Judiciary Committee, put it.

In the case of the 2015 video, Planned Parenthood said that its representative was merely discussing such legal charges and adamantly denied any wrongdoing. That did not stop Republicans, who controlled key congressional committees, including the Senate Judiciary Committee, from launching a series of investigations based on the video.

The Judiciary Committee’s report, “Human Fetal Tissue Research: Context and Controversy,” concluded that the executive branch had for years failed to exercise oversight on the tissue transfer process and created a situation where costs and fees were not properly accounted for. The report recommended that the Justice Department “fully investigate” the fetal tissue practices of Planned Parenthood, its affiliates, and three companies involved in the sale of the tissue for potential crimes.

Senator Charles E. Grassley, Republican of Iowa and the committee’s chairman, has said the referral fell on deaf ears at the Obama Justice Department. In a hearing this fall, he pressed Mr. Sessions to reconsider it. The attorney general said he would personally evaluate the referral “and make sure it is properly handled.”

The F.B.I. first requested unredacted documents from the committee last month, but Mr. Grassley requested that the department submit a formal letter.

Mr. Nadler, who was also a member of the special House committee assembled to investigate the issue, said he did not understand why the issue was being revisited.

“It is unclear what it expects to find after five congressional investigations, over a dozen of state investigations, and millions in taxpayer dollars found absolutely zero evidence of wrongdoing.”

A version of this article appears in print on , on Page A10 of the New York edition with the headline: Justice Dept. Investigating Fetal Tissue Transfers by Planned Parenthood and Others. Order Reprints | Today’s Paper | Subscribe